The invention relates to a faucet aerator with an aerator housing whose housing interior contains a flow-dispersing device with a plurality of through-flow holes for dispersing the incoming flow of water into a corresponding number of individual streams as well as at least one grid and/or lattice structure spaced apart from it in the flow direction; in the housing subregion situated between the flow-dispersing device (3) and the adjacent grid and/or lattice structure, a plurality of pins is provided, which are oriented in the flow direction, spaced apart from one another, and extend essentially over the distance between the flow-dispersing device and the adjacent grid and/or lattice structure.
Faucet aerators, which transform the water flowing from a sanitary outflow fixture into a homogeneous, non-spattering, and optionally also bubble-softened flow of water are already known in an extremely wide variety of designs. As a rule, these faucet aerators have an aerator housing that is embodied in the form of an insert cartridge and can be inserted into the water outlet of a sanitary outflow fixture and whose housing interior has a flow-dispersing device, for example embodied in the form of a perforated plate, situated at its inflow end and at least one grid and/or lattice structure situated downstream of it in the flow direction. This at least one grid and/or lattice structure, which can be a metal sieve or can also be embodied in the form of a plastic grid, can function as a flow-regulating device that mixes air into the individual streams issuing from the flow-dispersing device. In addition to or in lieu of this, at least one grid and/or lattice structure situated downstream of the flow-dispersing device can also be embodied in the form of a flow straightener whose function is to homogenize the flow of water issuing from the water outlet.
DE 201 15 636 U1 has already disclosed a faucet aerator, which, between a water inlet opening and a water outlet opening of its aerator housing, has a flow-dispersing device and a flow-regulating device situated downstream of it in the flow direction. The flow-dispersing device, which is embodied as a perforated plate with a plurality of through-flow holes, is followed by an insert piece that has an annular wall joined to a central element by means of a plurality of radial struts. A respective annular conduit is provided on the one hand between the annular wall and the housing wall of the aerator housing and on the other hand between the annular wall and the central element of the insert piece. In a step-shaped subregion, the annular wall has a multitude of pins that are situated on it in three concentric rings. Another concentric ring of pins is provided on the central element of the insert piece. The conically tapering ends of the pins point in the direction toward the flow-dispersing device and are each struck by one of the individual streams issuing from the flow-dispersing device in such a way that the pin-ends each constitute a deflecting bevel for the individual streams issuing from the through-flow holes of the flow-dispersing device. The pins provided in the previously known faucet aerator consequently have a chiefly jet-forming action on the water flowing through and, for purposes of decelerating, dividing, and air-mixing, are intended to function as flow obstacles for the individual streams that they deflect.
U.S. Pat. No. 7,217,362 B2 has already disclosed a faucet aerator, which has a perforated plate functioning as a flow-dispersing device at its downstream end and in the region of the water outlet opening of the aerator housing, has concentric annular walls that guide the flowing water into annular conduits situated between themselves. In this instance, pyramid-shaped projections are formed onto the inflow edge of the annular walls in the region of the water outlet opening; these projections are likewise intended to decelerate, divide, and thus mix air into the individual streams issuing from the flow-dispersing device. These pyramid-shaped projections previously known from U.S. Pat. No. 7,217,362 B2 therefore have a primarily jet-forming function.
Faucet aerators have also been produced, which have a non-round aerator housing with a greater housing width in comparison to the housing depth in order to produce a flow of water that issues from the water outlet in a wide ribbon.
In the previously known faucet aerators, there is sometimes the risk that even after the water valve is closed, water remaining in the aerator housing is exposed to the ambient air, which is sometimes dry, causing this residual water in the housing interior to evaporate, leaving behind an undesirable layer of scale. Over time, an undesirable layer of scale can build up on the interior of the aerator housing and particularly in the small flow-dispersing bores of the flow-dispersing device, which subsequently impairs the functionality of this faucet aerator or worse, prevents it from functioning at all.
The object of the invention, therefore, is in particular to create a faucet aerator of the type mentioned at the beginning, which is characterized by a malfunction-free operation, even over a long period of time.
In the faucet aerator of the type mentioned at the beginning, this object is attained according to the invention in that the pins each have an evaporation surface, which is situated outside the region that is struck directly by the individual streams but can be wetted by the water flowing through the aerator housing, and in that for this purpose, the pins are situated laterally outside the projection of the through-flow holes oriented in the flow direction.
In the housing subregion situated between the flow-dispersing device and the adjacent grid and/or lattice structure, the faucet aerator according to the invention has a plurality of pins that are oriented in the flow direction, spaced apart from one another, and extend over the distance between the flow-dispersing device and the adjacent grid and/or lattice structure. The term “pin” here is understood to mean any projection oriented approximately axially parallel to the flow direction, which can, for example, have a square cross-section or a rectangular or otherwise elongated cross-section, or can also be embodied as a wall section. Since the intent is for these pins to not significantly influence the current of water flowing through, but only after the flow of water is shut off, for them to constitute an evaporation surface that can be wetted by the water flowing through, the pins are thus situated laterally outside the projection of the through-flow holes of the flow-dispersing device, which are oriented in the flow direction. This arrangement of the pins in the housing interior of the aerator housing results in the fact that the pins are not struck directly by the individual streams, but instead, outside the subregion that is struck by the flow of the individual steams, function merely as an evaporation surface without a jet-forming function. These comparatively long pins or struts around which the flowing water circulates are covered by an enveloping water film even after the water valve is closed, resulting in an increased humidity and therefore a reduced evaporation in the housing interior of the aerator housing. It is particularly necessary to prevent an evaporation-induced scale formation in the small dispersing bores of the flow-dispersing device situated at the inflow end because otherwise, this results in a low-quality spray pattern and an insufficient ventilation of the water flowing through. The water pressure acting on faucet aerators of this kind is insufficient to break up such scale deposits and rinse them out of these small dispersing bores. Similar to the function of a “sacrificial anode” in the electrical engineering field, the pins provided according to the invention now constitute an evaporation surface that prevents an evaporation-induced scale formation in the vicinity of the small dispersing bores of the flow-dispersing device situated at the upstream end in the flow direction. Since this prevents a complete drying-out of the interior of the aerator housing in the times between water uses, thus preventing undesirable scale deposits on the housing interior of the aerator housing, the faucet aerator according to the invention is characterized by a high degree of functional reliability even over a long period of time.
Since the function of the pins provided in the faucet aerator according to the invention is not primarily a jet-forming one, it is useful if instead, the individual streams issuing from the flow-dispersing device each directly strike a respective intersecting node of the struts of the grid and/or lattice structure that cross one another at intersecting nodes and if for this purpose, the projections of at least more than half of the through-flow holes oriented in the flow direction are each aimed at a respective intersecting node.
So that the pins each constitute a relatively large surface that can be wetted by the water flowing through, it is advantageous if the ratio of the height h of the pins to the diagonal d—particularly at the base of the pins—is greater than 1.5, particularly greater than 2.0, and especially greater than 2.5.
In a preferred embodiment according to the invention, each pin has a total surface area of greater than 5 mm2, in particular greater than 7 mm2, and especially greater than 9 mm2. This surface area is a measure for the adhesion power that the pins exert on the water.
The pins according to the invention can be secured in any suitable fashion on the housing interior of the aerator housing. For example, these pins can be formed onto the underside or outflow side of the flow-dispersing device. In a preferred embodiment according to the invention, however, the pins are also or alternatively formed onto the outflow side of the flow-dispersing device and/or onto the inflow side of the adjacent grid and/or lattice structure.
In a preferred embodiment according to the invention, the grid and/or lattice structures that constitute the flow-regulating device each have a plurality of struts that are oriented transverse to the flow direction and delimit through-flow openings between themselves.
In one embodiment according to the invention in which the pins are formed solely onto the inflow side of the adjacent grid and/or lattice structure, it can be advantageous if the free ends of the pins point in the direction opposite from the flow direction for the sake of retaining the water, which remains in this housing subregion after the closing of the water valve, for a longer amount of time.
So that each individual pin is able to retain a comparatively large amount of water in the form of a film of water on the surface, it is advantageous if at least one pin has a nonround, preferably polygonal, and especially cruciform pin cross section. In this case, a cruciform pin cross section has the particular advantage that its cross section is adapted particularly well to the grid and/or lattice structure supporting it.
The pins can be clipped, glued, or welded to the struts of the adjacent grid and/or lattice structure or fastened to them in some other way. In a particularly simple and inexpensive-to-produce embodiment according to the invention, however, the pins are formed integrally onto the struts supporting them.
The struts forming a grid or lattice structure and the pins attached to them constitute a particularly advantageous functional unit if the struts supporting the pins form a through-flow plane oriented transversely and preferably at right angles to the flow direction.
In a preferred embodiment according to the invention, the struts supporting the pins are arranged in a grid- or lattice-like fashion in relation to one another, intersecting with one another at intersecting nodes.
In a particularly preferred embodiment according to the invention, the struts supporting the pins form the through-flow plane at the inflow end of the flow-regulating device and are preferably situated immediately downstream of a flow-dispersing device in the flow direction.
So that the flow-regulating device is able to achieve a particularly favorable mixing of air into the individual streams issuing from the flow-dispersing device, it is advantageous if the flow-regulating device has a plurality of insert pieces that are embodied as grid- or lattice-like and have struts that intersect with one another at intersecting nodes.
In a preferred embodiment according to the invention, the preferably aerated faucet aerator has a flow-dispersing device at its inflow end and a flow-regulating device connected downstream of the latter and optionally, a flow straightener is connected downstream of the flow-regulating device.
So that the air flowing into the housing interior is able to easily pass through the rows of pins and as a result, the air drawn in by the faucet aerator can be evenly distributed over the entire cross section of the aerator housing, it is useful if a plurality of rows of parallel pins is provided and if, in comparison to the pins of the inner pin rows, the pins of the outer pin rows preferably have a shorter longitudinal span and/or a greater spacing from one another.
The invention will be explained in detail below in conjunction with a preferred exemplary embodiment. Other defining characteristics according to the invention ensue from the subsequent drawings considered in connection with the claims and the description.